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If enough of a monoprotic acid is dissolved in water to produce a 0. 0186 m solution with a ph of 6. 44 , what is the equilibrium constant, ka, for the acid?

Respuesta :

The equilibrium constant, ka, for the monoprotic acid is 7.08 × 10⁻¹⁶.

How do we calculate Ka?

Acid dissociation constant (Ka) for monoprotic acid will be calculated according to the given equation:

Ka = [H₃O⁺][A⁻] / [HA]

Relation between H₃O⁺ and pH will be represented as:

[H₃O⁺] = [tex]10^{-pH}[/tex]

pH = 6.44 (given)

[H₃O⁺] = [tex]10^{-6.44}[/tex] = 3.63×10⁻⁷

Given chemical reaction with ICE table is:

                      HA(aq)  +  H₂O(l)  ⇄  H₃O⁺(aq)  +  A⁻

Initial:            0.0186                               0            0

Change:        -3.63×10⁻⁷                   3.63×10⁻⁷   3.63×10⁻⁷

Equilibrium: 0.0186-3.63×10⁻⁷         3.63×10⁻⁷   3.63×10⁻⁷

Now Ka for this will be:

Ka = (3.63×10⁻⁷)² / (0.0186-3.63×10⁻⁷)

Value of 3.63×10⁻⁷ is negligible as compared to the 0.0186 value and equation becomes,

Ka = (3.63×10⁻⁷)² / 0.0186 = 13.18 × 10⁻¹⁴ / 0.0186

Ka = 7.08 × 10⁻¹⁶

Hence value of equilibrium constant is 7.08 × 10⁻¹⁶.

To know more about equilibrium constant, visit the below link:
https://brainly.com/question/12858312

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